Command terms

Every question on an ESS paper begins with a command term: a verb such as “state”, “explain” or “evaluate” that tells you what kind of answer is wanted. The command term sets the depth of the answer, and the mark allocation in square brackets tells you how many separate points the markscheme is looking for. Two students with the same knowledge can score very differently because one answers the command term and the other writes everything they know about the topic.

Each command term has a fixed meaning set by the IB, and that meaning does not change from one question or paper to the next. Learning those meanings, and what an answer to each one looks like in ESS, is one of the quickest ways to raise your marks on both papers.

What command terms do

Command terms are grouped by the assessment objectives (AOs) they test. AO1 terms ask you to recall knowledge, such as a definition or a name. AO2 terms ask you to apply and analyse it, such as describing a trend in data or calculating a value. AO3 terms ask you to evaluate and synthesise: to explain causes, weigh up strengths and limitations, and reach a supported judgement. A fourth objective, AO4, covers investigative skills and is assessed mainly through the individual investigation.

As the cognitive demand rises, the number of marks and the length of answer expected usually rise too. A “state” question is often worth 1 mark and needs a few words. An “evaluate” or “to what extent” question at the end of an essay is worth 9 marks and needs several developed paragraphs with a conclusion.

How marks are awarded

Short and structured questions are marked with a markscheme: a list of acceptable points, usually one mark each, up to the total in brackets. If an “Outline two…” question is worth [4], the markscheme typically gives 1 mark for each of two valid points and 1 mark for developing each one. If an “Explain” question is worth [3], it usually wants three linked steps in a chain of reasoning, or one point explained in enough depth to earn three marks.

The last part of each Paper 2 Section B essay is marked differently, with markbands. The examiner reads the whole answer and matches it to the band whose description fits best: the breadth and accuracy of knowledge, the use of examples, the balance of the analysis and the quality of the judgement. Counting points does not work there. The command terms that appear in that part (“evaluate”, “discuss”, “to what extent”, “examine”, “justify”) all ask for a judgement.

AO1 terms: knowledge and recall

AO1 command terms ask for precise knowledge without reasons. Answers are short, and the marks go to accuracy and the correct ESS terminology.

Define

A definition earns its mark only if it is precise. Vague, everyday meanings are not enough, and examples alone are not a definition. The safest approach is to learn the definitions of the key terms of each topic word for word as they appear in the glossary, including the qualifiers that make them precise.

State and list

“State” and “list” want brief answers with no explanation. A reason added to a “state” answer earns nothing, although it does not usually lose marks either. The risk is time: a student who explains every “state” answer may run short at the end of the paper.

Draw, label and measure

“Draw” means an accurate, labelled diagram or graph. For a graph, the axes are labelled with the quantity and its units, the scale is even, and points are plotted correctly. For a systems diagram, storages are boxes and flows are labelled arrows. An unlabelled diagram, however neat, usually earns very little.

“Label” asks only for names placed on a diagram that is already given. “Measure” asks you to read a value, for example the length of a transect on a scaled diagram or a value from a graph, and to give it with units.

AO2 terms: application and analysis

AO2 command terms ask you to use your knowledge: to describe what data show, calculate from them, tell concepts apart, or apply an idea to a new situation. Most Paper 1 questions and many Paper 2 Section A questions use them.

Identify, calculate and estimate

“Identify” is a selection task: the answer is somewhere in the resource or among a small set of possibilities, and the mark is for picking the right one. “Calculate” always needs working. “Estimate” accepts an approximate value, but it should still be reasoned from the data rather than guessed.

Outline, describe and explain

These three terms are the ones students confuse most, and they appear on almost every paper. They ask for the same topic at three increasing depths. “Outline” gives a brief account. “Describe” gives a detailed account of what happens or what the data show, but without reasons. “Explain” adds the reasons or causes: the “why” or “how”.

Strictly, “explain” is an AO3 term, but it belongs with the other two because questions so often move from one to the next. The difference is easiest to see when the same topic is asked three ways.

Describing data well

“Describe” questions on graphs and tables are common on Paper 1. A strong description gives the overall trend first, then supports it with values (start, end, maximum, minimum) and dates, then notes changes in the rate of change and any anomalies. It does not explain. Describing trends, gradients and rates of change is practised in more depth in “Calculations and data skills”.

Distinguish

“Distinguish” wants the differences between two things, and the marks go to statements that make a difference clear. Two separate definitions, one after the other, leave the examiner to find the difference, and often lose marks. Each sentence should mention both items and use a contrast word such as “whereas” or “while”.

Annotate and label

“Label” asks for names; “annotate” asks for brief notes that explain. On a graph, an annotation says why a section looks the way it does or what is happening at a point. Annotations should be on the figure itself, next to the feature, and short enough to fit.

Interpret and apply

“Interpret” goes one step beyond describing data: you recognise the trend and then draw a conclusion from it using ESS knowledge. “Apply” asks you to use a named idea, model or equation on the situation in front of you, often an unfamiliar place in a Paper 1 resource booklet.

AO3 terms: evaluation and synthesis

AO3 command terms ask you to reason: to explain causes, to break an issue into its parts, to compare, to weigh evidence and to reach a judgement. They carry the most marks. The table gives every AO3 and AO4 term with what it looks like in an ESS answer; the most common ones are worked through after it.

Explain

An explanation is a chain. Each link answers “why?” or “how?” for the link before it, and the last link reaches the outcome the question asks about. In a 3- or 4-mark question, each well-made link is usually one marking point. Explanations score best when they use the precise ESS process names, such as evapotranspiration, positive feedback or biomagnification, because these are the words in the markscheme.

Suggest, predict, deduce and determine

“Suggest” is the most open of all command terms. It asks for a plausible answer that fits the context, and markschemes usually accept a range of answers, including ones the examiner did not list, if they are reasonable. Paper 1 uses it often, because the place in the resource booklet is unfamiliar and there is no single right answer.

“Predict” wants an expected result, ideally with a direction and a size. “Deduce” wants a conclusion that follows logically from the information given, and “determine” wants the only possible answer, often a single value read or worked out from data.

Compare and contrast

“Compare and contrast” asks for both similarities and differences, and requires you to refer to both items throughout. An answer with only differences usually cannot reach full marks. Writing one paragraph about each item separately is the most common way to lose marks: each sentence should mention both items.

Construct, sketch, draw and design

These four terms all ask you to produce something. “Draw” wants an accurate diagram or graph, with points plotted correctly. “Sketch” wants the right general shape and the key features labelled, but not exact values. “Construct” wants information, often from given data, organised into a diagram or logical form: a systems diagram, a food web, a pyramid or a table. “Design” wants a plan, such as a sampling method or a management scheme.

Analyse and examine

“Analyse” wants an issue broken into its essential parts and the relationships between them. For data, that may mean separating the trend from the anomalies or comparing two sites; for an issue, it may mean separating the causes, the stakeholders or the parts of a system. “Examine” goes further: it asks you to uncover the assumptions and interrelationships behind an argument. An examine answer asks what has to be true for a claim to work, who benefits and who does not, and how the factors depend on each other.

Justify, comment and demonstrate

“Justify” wants reasons and evidence that support a stated choice or conclusion: the answer should end in the choice and show why it is the right one. “Comment” wants a short judgement on a statement or a calculated result, such as whether a value is high or low and what that shows. “Demonstrate” wants a point made clear by reasoning and an example.

Evaluate, discuss and to what extent

These three terms appear in the 9-mark final parts of Section B essays and in the longer questions at the end of Paper 1. All three end in a supported judgement, but they ask for slightly different things, and an answer that recognises the difference reads as more focused.

• Evaluate asks for an appraisal of a strategy, model, method or policy by weighing its strengths and limitations. The conclusion answers “how useful, effective or sustainable is it, and under what conditions?”.

• Discuss asks for a balanced review of a range of arguments, factors or hypotheses, often from several perspectives. The conclusion states your view and supports it.

• To what extent asks how far a claim or argument holds. The answer considers the merits and limits of the claim and ends with a clear position on a scale: fully, largely, partly or hardly at all.

Weak and strong paragraphs compared

The example question is “Evaluate the use of fishing quotas as a strategy for managing a fishery sustainably. [9]”. The two paragraphs make the same basic point; only the second is evaluating.

Bringing in perspectives

In ESS, a balanced answer is usually balanced between perspectives as well as between arguments. A technocentric view may welcome a technological fix such as desalination, an ecocentric view may stress its impact on marine ecosystems and its energy use, and an anthropocentric view may judge it by its cost and who gets the water. Naming the perspective and saying what it values shows the examiner the analysis is balanced. HL students strengthen this further with legal, economic and ethical angles from the HL lenses.

Confusable command terms

The table sets out the pairs and groups that cost the most marks, with the one difference that matters.

A routine for every question

Most lost marks come from misreading the question, not from missing knowledge. A routine that takes a few seconds per question prevents most of them.

1. Find the command term and underline it. Decide what kind of answer it wants: a name, a description, a reason, a calculation or a judgement.

2. Check the marks. Plan roughly one point per mark, and one extra on longer questions.

3. Underline the focus words: the exact topic, place, time period or number of items (“two”, “in the resource”, “for a named ecosystem”).

4. Check for an instruction to use the resource. “Using Figure 3” or “With reference to the data” means marks are given for quoting values from it.

5. Answer, then reread the question. Check the answer does what the command term asks, uses ESS terminology and gives units with every number.

Common mistakes with command terms

The opposite error is just as costly. A one-sentence answer to an “evaluate” question, even if correct, cannot reach the higher bands because it gives neither strengths and limitations nor a judgement.

Two more errors appear often in data questions: describing a graph without quoting any values, and giving numbers without units. Both are easy to fix with a final check of each answer.

Key points

• The command term tells you the kind and depth of answer; the marks tell you roughly how many points to make.

• AO1 terms (define, state, list, label, draw, measure) ask for precise knowledge without reasons.

• AO2 terms (outline, describe, identify, calculate, distinguish, annotate, interpret, apply, estimate) ask you to use knowledge and data.

• AO3 terms (explain, analyse, suggest, justify, compare and contrast, construct, evaluate, discuss, examine, to what extent) ask for reasoning and judgement.

• Describe gives what happens, with values; explain adds why.

• Distinguish wants differences only; compare and contrast wants similarities and differences, referring to both throughout.

• Evaluate, discuss and to what extent all end in a supported judgement written in the words of the question.

• Short questions are point-marked with a markscheme; the 9-mark essay parts are marked with markbands that reward examples, balance and a reasoned conclusion.